The invention concerns a cardioplegic controlling and regulating device for dosed perfusing of cardioplegic perfusion solution, especially in open-heart operations. The device comprises a storage container for the cardioplegic solution which is connected by means of a fexible tubular line to the patient's heart and also comprises at least one pressure-controlled dosing pump which acts on the tubular line, as well as a take-off line which removes the blood mixed with the cardioplegic solution accumulated in the patient's heart and is dispensed into a suitable collector vessel.
Known devices of this type are used in an operating technique in open-heart surgery in which an artificially induced, reversible cardiac arrest is produced by perfusion of a cardioplegic solution. The blood in the coronary vessels of the heart is completely replaced in such a procedure by the perfused cardioplegic solution. The exchange of the blood by the cardioplegic solution is performed by at least one catheter introduced into certain areas of the heart for supplying the cardioplegic solution and by at least one catheter for removing the blood which is mixed and enriched with cardioplegic solution in accordance with the progress of the perfusion process.
The medical and technical background is treated in "Myocardial `Equilibration Processes` and Myocardial Energy Turnover during Initiation of Artificial Cardiac Arrest with Cardioplegic Solution-Reasons for a Sufficiently Long Cardioplegic Perfusion", published in Thoraci Cardiovascular, Surgeon, 1981, pp. 71-6. Note also sources 1 to 29 cited in this article.
State-of-the-art devices are known which operate with one or with two pressure-controlled dosing pumps. Both the systems with a single pressure-controlled pump and also systems incorporating two pressure-controlled pumps have the following disadvantages from a medical and a technical viewpoint:
1. The preparation time until the cardiac arrest is too long, so that the patient is put under unnecessary strain.
2. The cardiac arrest time available for the actual open-heart surgery is too short, so that protracted and complicated operations can not be performed and simple operations which suddenly develop complications must be terminated too soon.
3. The actual perfusion is not as stress-free from a medical viewpoint as the condition of the patient actually requires.
4. The heart surgeon can exercise no regulating influence in the known devices in phase A, in which the cardiac arrest is achieved or in phase B, in which the perfusion must be completed by a reduced pump volume and a reduced pressure.
5. The patient's blood from the coronary vessels which accumulates during the operation (approximately 1 liter) is disposed of due to its being mixed with the cardioplegic solution and the possibility of an embolism after the end of the perfusion process, since the previously known cardioplegic controlling and regulating systems have no facilities for returning to the patient the blood which was withdrawn from him and is now mixed with the cardioplegic solution. This is at the expense of the patient and is unsatisfactory due to the lack of a technical solution.